When the condition of syringomyelia was first described, it was believed that the accompanying symptoms were distinctive and characteristic, and that the peculiar sensory dissociation observed was pathognomonic, but time and experience have not unqualifiedly sustained these earlier notions. It has been abundantly shown, clinically and pathologically, that the symptoms, except as to their mode of onset and course, bear no relation to the process itself or to the nature of the lesion, but rather to its situation and extent. So-called syringomyeliac symptoms have been observed in association with cavities, neoplasms, hemorrhages, traumatism and other lesions of the spinal cord; and the manifestations vary in accordance with the structures involved. Most often the multipolar ganglioncells of the anterior horns of the cervical cord are affected, so that weakness and wasting of muscles in the upper extremities result; while involvement of the adjacent pyramidal tracts gives rise to spastic phenomena; and